Continued Vibration

[DocD]

I am wondering about a rotary mower I just bought. When I hooked it up, I noticed a large amount of vibration. that read most of the threads and have lubed the blade pivot points and it definitely made a big difference. Still, there is a rhythmic vibration even at high speed. I have a 3720 cab, so I think I notice it more as the cab shakes. Does anyone have any more suggestions as it is a new KK 72' rotory mower and I am wondering if there is anything else to do or check? Also, how much vibration would itt take to do damage?

 

[AndyMA]

I am wondering about a rotary mower I just bought. When I hooked it up, I noticed a large amount of vibration. that read most of the threads and have lubed the blade pivot points and it definitely made a big difference. Still, there is a rhythmic vibration even at high speed. I have a 3720 cab, so I think I notice it more as the cab shakes. Does anyone have any more suggestions as it is a new KK 72' rotory mower and I am wondering if there is anything else to do or check? Also, how much vibration would itt take to do damage?

What type of mower is it? A single spindle "Brush Hog" type or a multiple spindle finish mower? I'm guessing brush hog type. They do vibrate some especially if they are out of balance or the blades don't fully extend from the stump jumper when spinning. Check to make sure both blade halfs appear to be the same size. You may want to take them off and weigh them. When I've broken a blade tip the thing almost jumps off the ground. In balance pretty smooth.

Andy

 

[easygo]

If you have it greased up then my vote would be on the same issue as AndyMa mentioned. If the blades are out of balance then it needs to be addressed. That can be the same issue for anything including a little push-mower. If you happen to chip pieces out of one side and it needs to be sharpened more then the other it will happen unless one is careful to take the same amount of material from both (all) cutting edges.

 

[teg]

You have "...lubed the blade pivot points..." so I'm guessing you had the blades off to do that. Remove the blades again, to weigh them but go ahead and run the mower without blades to see if you still have a vibration. How do the blades look? New or do they show some age?

 

[Farmwithjunk]

The quality control on King Kutter mowers has been know to be a little lax. Not uncommon to find them slightly less than perfect. This is one of the subtle differences between low end and upper end price range mowers. Quality is generally just a bit more consistant with the higher priced mowers (but not ALWAYS)

Start by checking blades for level and true in relation to mower deck. Measure blade tip to deck on each blade at various points around their rotation. Measurements should be the same on BOTH blades at ALL points of the rotation. Variation may indicate the stumpjumper being bent, mis-shapen, or out of level, bent gearbox output shaft, or possibly a bent blade.

Also check the pto shaft. I've seen a cases where the shaft would hit the leading edge of the mower deck when the 3-point lift is raised all the way. That can bend the pto shaft. A few years back I bought a used mower at an auction. It had a terrible vibration in it. I found an improperly installed U-joint to be the cause of that one.

If EVERYTHING checks out ok, try using the mower some. Not uncommon for new/low use mowers to vibrate some until blades free up on their own, from use, on the pivots points.